Printed Electronics and Devices Alaska

Stretchability is needed in electronics if it is to be foldable, tightly conformal or following the form of something that changes in shape, like the human body. It is needed for uses from healthcare to toys and robots.

Tokyo University has put a rubbery sheet containing pressure sensors on top of a sheet of plastic transistors, which was then wrapped around the fingers of a robot's hand. To make an effective human skin the substrate needs to be able to stretch and Dr Stephanie Lacour, a researcher at the University of Cambridge, UK and the University of Princeton Professor Sigurd Wagner, found that gold deposited on silicone rubber could stretch by up to 100% without breaking the connection and 20% without increasing electrical resistance. Human skin stretches about 10%.

The Technical University of Berlin used wavy patterns of metal to let the material stretch but Lacour discovered that microcracks in the gold may not be the only material that can produce stretchy electronics. "If you can get this microcrack structure into any material then it should stretch in the same way," asserts Lacour. She is now working on a way to combine it with conventional electronics and sensors. Islands of a stiffer material on the silicone can carry micro chips and thin film transistors printed directly on the material.

"There will be a lot of applications in robotics and consumer products and a lot of people are interested in stretchable displays," she says. It will help mend broken nerves and as a sensory skin for prosthetic limbs she told IET Magazine. "With nerves in limbs we know these nerves regenerate, but they sometimes reconnect the wrong cells. We are looking at ways to re-route them by having an implant that lets us work out which nerves should be connected to each other." Stretchy, flexible substrate is needed to cope with the movement of the body: "We need to work with much softer materials than a silicon wafer."

Stretchable electronics could find many uses in medicine. Alain Bouffioux a researcher at NXP Semiconductors has helped the EU-funded Stella project developing stretchable technologies. He notes, "One potential application is in baby respiration monitoring to guard against sudden infant death syndrome. The baby's apparel could contain strain sensors to monitor how it breathes and then raise an alarm if it suddenly stops or becomes erratic. The "My Heart" project has electrodes built into a vest to provide electrocardiogram readings.

Work on Stella has focussed on putting conventional electronic components inside a silicon rubber bandage. Beyond that it will be possible to put transistors into the fibres of clothes and knit a circuit. Indeed Eleksen has put electrical wiring and keypads into textiles, to make jackets that carry the audio from an iPod in a special pocket to headphones attached to the collar, with a remote control printed on the sleeve.

Professor of Annalisa Bonfiglio of the University of Cagliari in Italy reckons the combination of electronics and apparel can go much further not least because of the stretchability of weaving. Her team has developed a doughnut-like organic transistor wrapped around conductive fibres and sealed inside an insulated coating. To wire up this "textile transistor", production equipment may knit or weave the fibres together and cut through the insulation at contact points to produce electrical circuits.


http://www.idtechex.com/printedelectronicsworld/articles/advances_in_stretchable_electronics_00000695.asp

Drug Anticounterfeiting by RFID

It was sad that the Food and Drug Administration backed off from urgently pushing through standards and rapid adoption of RFID at item level on drugs, after its earlier firm lead in 2005-6. However, its recommendation remains but with industry left to set the pace. For now, the US pharmaceutical industry and the FDA have decided that RFID is too expensive for general use and DataMatrix™ barcodes will do, although IDTechEx notes that these will be far more susceptible to misorientation, dirt and damage and often they will not be automatically read if only because they must be read one at a time. That means that checks on counterfeits by what is called "mass singulation" will be far less frequent than with RFID (mass singulation means every pot of pills and blisterpack has a unique number for reverse audit of "pedigree"). The European pharmaceutical associations have a similar view and Europe has a less effective regulatory regime anyway with no central alternative to the FDA.

At a recent IDTechEx conference, Impinj, the UHF RFID company, quoted the cost of pharmaceutical counterfeits as $75 billion worldwide by 2010 according to Frost and Sullivan. Impinj said that the recent Vioxx recall was 120% of tablets made. IDTechEx has seen reports that a few counterfeits have even been dispensed through national pharmacy chains in the USA. That is a new and ugly prospect and hundreds of thousands more lives are at stake as the attacks continue to increase. Health Industry Insights reports that 'Leaky' channel management costs the pharma industry 4.5% of revenue. Poor reconciliation of charge-backs, plus faulty product-returns crediting, are the sources.

To its credit, Impinj is trialling UHF RFID at pallet, case and item level with six out of the top ten pharmaceutical companies. Near Field UHF is increasingly used to save cost and avoid problems with water and metal. Tagsys is trialling HF RFID in similar applications with many pharmaceutical companies and recent press reports that GlaxoSmithKline is disillusioned with its RFID on Trizivir™ are plain wrong. GlaxoSmithKline says it is scaling up after excellent results. However, we do need a standard for both tag system and secure database. To its discredit, EPCglobal is taking years to establish a standard for EPC at HF, the world's most popular frequency for RFID, but it is getting there. Meanwhile, Impinj and others are able to use fully established EPC "Gen2" UHF standards and procedures and it reports 100% reads of plastic bottles of pills in cases and of the cases themselves.

Impinj partners include:

• Weiler Label Systems: High speed labeling equipment
• Systech International: Production line control software
• CCL, Cortegra , George Schmitt & Co., Nosco: Finished labels
• Rexam Plastic Packaging (Owens-Illinois): RFID-embedded pharma bottle
• HP Technology Consulting, Verisign: Project management; Business process consulting.

http://www.idtechex.com/printedelectronicsworld/articles/drug_anticounterfeiting_by_rfid_00000703.asp

Battery System Monitor

Once you get beyond the simplest renewable energy system, it is necessary to include some battery bank monitoring equipment. Batteries are one of the most expensive and fragile components of a renewable energy system, and so it is essential that their status is carefully monitored. It is also very useful to track the charge coming in from the various sources in a combined system - usually photovoltaic solar panels and wind turbine generators - in order to see from where you are getting power.

Probably the best known battery system monitor is the Bogart Engineering Tri-Metric 2020 Battery System Monitor. This device displays battery voltage, amps, amp-hours, battery percent full, and five other data functions, and works with systems from 12V to 48V for around £100. Great value as it costs the same as one decent battery and should increase the lifetime of your batteries:

Bogart Engineering have now introduced the new PentaMetric Battery Monitor which offers even more capability than the TriMetric.

Another alternative if you are on a limited budget is a simple digital multimeter. Available from just £5, a digital multimeter can be used to measure the voltage of your battery bank, and the current (amps) being put into or drawn from the batteries when being charged or under load.

http://www.reuk.co.uk/Battery-System-Monitor.htm

Shunt Regulator

A Shunt Regulator is a small electronic component that clamps a power supply voltage at a fixed level. Hundreds of times per second it checks the power supply voltage, and if the voltage is over the limit (set by adding a couple of resistors to the regulator in a small circuit) then the extra voltage is bled off through a resistor. If the voltage is below the fixed maximum, then no current passes through the resistor.

How can shunt regulators be useful to alternative energy generators. Well, for example a solar panel rated at 12V will actually generate up to 20V. If this panel is to be connected directly to equipment requiring an input of 12V, that equipment could be damaged if the voltage is too high. Therefore, by passing the solar panel's generated current through a shunt regulator circuit, the voltage reaching the equipment can be clamped at 12V very accurately.

Rather than dumping the excess power into a resistor and losing it in the form of dissipated heat, it is possible to put it to better use, for example to heat or pump water.

A common shunt regulator used in solar applications is the LM431. This is a 3-terminal adjustable shunt regulator which can have its output voltage set to any value between 2.5 and 36V by the correct selection of two resistors. LM431's are available for example from eBay at just $4.50 for 25.


http://www.reuk.co.uk/Shunt-Regulator.htm